A study of the spectral sensitivity of retinal ganglion cells in the cat has been made using strong chromatic adaptation and spatial localization of the stimulus to the receptive center and/or periphery. The results have shown that three independent and chromatically distinct cone receptor systems: appear to converge on many if not all ganglion cells in the retinas of cats. Most show simple additivity rather than opponency in the same region of the receptive field. A rare cell did show opponency however.